Port in use problem (Mac)

Bild von Hannu Visti


Is there a solution to the "port in use" problem that seems to be troubling also others than me?  The system is Mac (Lion) and GPS device is Blumax gps-4044.   I've set up the bluetooth connection and these devices were created:

crw-rw-rw-  1 root  wheel   18,   7 21 Sep 16:51 /dev/cu.iBTAGPS-SPPslave-1

crw-rw-rw-  1 root  wheel   18,   6 21 Sep 16:27 /dev/tty.iBTAGPS-SPPslave-1

If I just cat the device (cat /dev/tty/iBTAGPS-SPPslave-1, the bluetooth connection is set up and data starts to appear.  However, if I try to connect BT747, I always get the port in use error:1600837 - Classgps.connection.GPSRxTxPortInfo: trying to open '/dev/cu.iBTAGPS-SPPslave-1'Error: Port /dev/cu.iBTAGPS-SPPslave-1is currently in usegnu.io.PortInUseException: Unknown ApplicationReboots etc don't help at all.  Is there a workaround to this?  I've tried the latest release and development version of BT747 but the result is always the same. /hv

Bild von mdeweerd

Hi If the port is in use then


If the port is in use then this can be due to:

1. Another instance of BT747 keeping the port open;

2. Another program keeping the port open - quite often that is 'gpsd'.


You'ld have to identify the program that opens the port.  There is a 'unix' program that can identify which program has an open handle, I do not remember the name right now.  As far as I remember the same one can be made available on Mac.

I know this is an extremely

I know this is an extremely old question. However I am having the exactly same problem. I am on Mac OSX 10.11.5 and try to connect to a Holux M1000c. How can I find out why the port is already in use? Or is it some sort of driver error?

Bild von mdeweerd

One of the tools existing on

One of the tools existing on unix like systems to find out which program is using a "filesystem" resource or network resource, is "lsof".


It seems that it is pre-installed on mac, so you have to do a "lsof /dev/<port>" (in a terminal)  which should provide a process id and then you can lookup this process id to find the corresponding program that is locking the port.